From: Brijesh Singh <brijesh.singh@amd.com>
To: Peter Gonda <pgonda@google.com>
Cc: brijesh.singh@amd.com, x86@kernel.org,
linux-kernel@vger.kernel.org, kvm list <kvm@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
jroedel@suse.de, "Lendacky, Thomas" <thomas.lendacky@amd.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@intel.com>,
David Rientjes <rientjes@google.com>,
Sean Christopherson <seanjc@google.com>,
peterz@infradead.org, "H. Peter Anvin" <hpa@zytor.com>,
tony.luck@intel.com
Subject: Re: [PATCH Part2 RFC v2 32/37] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT
Date: Mon, 10 May 2021 15:50:57 -0500 [thread overview]
Message-ID: <c8aaede1-1eff-03ad-605b-ac5ce0355712@amd.com> (raw)
In-Reply-To: <CAMkAt6rfnjqPZHUqJM1r6GjnBMy-Gbw8VtGv4gd-G0Rjq+ALnQ@mail.gmail.com>
On 5/10/21 2:59 PM, Peter Gonda wrote:
> On Mon, May 10, 2021 at 11:51 AM Brijesh Singh <brijesh.singh@amd.com> wrote:
>> Hi Peter,
>>
>> On 5/10/21 12:30 PM, Peter Gonda wrote:
>>>> +static int snp_make_page_shared(struct kvm_vcpu *vcpu, gpa_t gpa, kvm_pfn_t pfn, int level)
>>>> +{
>>>> + struct rmpupdate val;
>>>> + int rc, rmp_level;
>>>> + struct rmpentry *e;
>>>> +
>>>> + e = snp_lookup_page_in_rmptable(pfn_to_page(pfn), &rmp_level);
>>>> + if (!e)
>>>> + return -EINVAL;
>>>> +
>>>> + if (!rmpentry_assigned(e))
>>>> + return 0;
>>>> +
>>>> + /* Log if the entry is validated */
>>>> + if (rmpentry_validated(e))
>>>> + pr_debug_ratelimited("Remove RMP entry for a validated gpa 0x%llx\n", gpa);
>>>> +
>>>> + /*
>>>> + * Is the page part of an existing 2M RMP entry ? Split the 2MB into multiple
>>>> + * of 4K-page before making the memory shared.
>>>> + */
>>>> + if ((level == PG_LEVEL_4K) && (rmp_level == PG_LEVEL_2M)) {
>>>> + rc = snp_rmptable_psmash(vcpu, pfn);
>>>> + if (rc)
>>>> + return rc;
>>>> + }
>>>> +
>>>> + memset(&val, 0, sizeof(val));
>>>> + val.pagesize = X86_TO_RMP_PG_LEVEL(level);
>>> This is slightly different from Rev 2.00 of the GHCB spec. This
>>> defaults to 2MB page sizes, when the spec says the only valid settings
>>> for level are 0 -> 4k pages or 1 -> 2MB pages. Should this enforce the
>>> same strictness as the spec?
>>
>> The caller of the snp_make_page_shared() must pass the x86 page level.
>> We should reach here after all the guest provide value have passed
>> through checks.
>>
>> The call sequence in this case should be:
>>
>> snp_handle_vmgexit_msr_protocol()
>>
>> __snp_handle_page_state_change(vcpu, gfn_to_gpa(gfn), PG_LEVEL_4K)
>>
>> snp_make_page_shared(..., level)
>>
>> Am I missing something ?
> Thanks Brijesh. I think my comment was misplaced. Looking at 33/37
>
> +static unsigned long snp_handle_page_state_change(struct vcpu_svm
> *svm, struct ghcb *ghcb)
> +{
> ...
> + while (info->header.cur_entry <= info->header.end_entry) {
> + entry = &info->entry[info->header.cur_entry];
> + gpa = gfn_to_gpa(entry->gfn);
> + level = RMP_TO_X86_PG_LEVEL(entry->pagesize);
> + op = entry->operation;
>
> This call to RMP_TO_X86_PG_LEVEL is not as strict as the spec. Is that OK?
I am not able to follow which part of the spec we are missing here. Can
you please elaborate it a bit more - thanks
The entry->pagesize is boolean, so, the level returned by the macro is
either a 4K or 2MB.
next prev parent reply other threads:[~2021-05-10 20:51 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-30 12:37 [PATCH Part2 RFC v2 00/37] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 01/37] KVM: SVM: Add support to handle AP reset MSR protocol Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 02/37] KVM: SVM: Provide the Hypervisor Feature support VMGEXIT Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 03/37] KVM: SVM: Increase the GHCB protocol version Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 04/37] x86/cpufeatures: Add SEV-SNP CPU feature Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 05/37] x86/sev: Add the host SEV-SNP initialization support Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 06/37] x86/sev: Add RMP entry lookup helpers Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 07/37] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 08/37] x86/sev: Split the physmap when adding the page in RMP table Brijesh Singh
2021-05-03 15:07 ` Peter Zijlstra
2021-05-03 15:15 ` Andy Lutomirski
2021-05-03 15:41 ` Dave Hansen
2021-05-07 11:28 ` Vlastimil Babka
2021-04-30 12:37 ` [PATCH Part2 RFC v2 09/37] x86/traps: Define RMP violation #PF error code Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 10/37] x86/fault: Add support to handle the RMP fault for kernel address Brijesh Singh
2021-05-03 14:44 ` Dave Hansen
2021-05-03 15:03 ` Andy Lutomirski
2021-05-03 15:49 ` Brijesh Singh
2021-05-03 15:37 ` Brijesh Singh
2021-05-03 16:15 ` Dave Hansen
2021-05-03 17:19 ` Brijesh Singh
2021-05-03 17:31 ` Brijesh Singh
2021-05-03 17:40 ` Andy Lutomirski
2021-05-03 19:41 ` Brijesh Singh
2021-05-03 19:43 ` Dave Hansen
2021-05-04 12:31 ` Brijesh Singh
2021-05-04 14:33 ` Dave Hansen
2021-05-04 15:16 ` Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 11/37] x86/fault: Add support to handle the RMP fault for user address Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 12/37] crypto:ccp: Define the SEV-SNP commands Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 13/37] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 14/37] crypto: ccp: Shutdown SNP firmware on kexec Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 15/37] crypto:ccp: Provide APIs to issue SEV-SNP commands Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 16/37] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Brijesh Singh
2021-05-10 18:23 ` Peter Gonda
2021-05-10 20:07 ` Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 17/37] crypto: ccp: Handle the legacy SEV command " Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 18/37] KVM: SVM: make AVIC backing, VMSA and VMCB memory allocation SNP safe Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 19/37] KVM: SVM: Add initial SEV-SNP support Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 20/37] KVM: SVM: define new SEV_FEATURES field in the VMCB Save State Area Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 21/37] KVM: SVM: Add KVM_SNP_INIT command Brijesh Singh
2021-05-06 20:25 ` Peter Gonda
2021-05-06 22:29 ` Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 22/37] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 23/37] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_UPDATE command Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 24/37] KVM: SVM: Reclaim the guest pages when SEV-SNP VM terminates Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 25/37] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_FINISH command Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 26/37] KVM: X86: Add kvm_x86_ops to get the max page level for the TDP Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 27/37] KVM: X86: Introduce kvm_mmu_map_tdp_page() for use by SEV Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 28/37] KVM: X86: Introduce kvm_mmu_get_tdp_walk() for SEV-SNP use Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 29/37] KVM: X86: Define new RMP check related #NPF error bits Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 30/37] KVM: X86: update page-fault trace to log the 64-bit error code Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 31/37] KVM: SVM: Add support to handle GHCB GPA register VMGEXIT Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 32/37] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT Brijesh Singh
2021-05-10 17:30 ` Peter Gonda
2021-05-10 17:51 ` Brijesh Singh
2021-05-10 19:59 ` Peter Gonda
2021-05-10 20:50 ` Brijesh Singh [this message]
2021-04-30 12:38 ` [PATCH Part2 RFC v2 33/37] KVM: SVM: Add support to handle " Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 34/37] KVM: X86: Export the kvm_zap_gfn_range() for the SNP use Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 35/37] KVM: SVM: Add support to handle the RMP nested page fault Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 36/37] KVM: SVM: Provide support for SNP_GUEST_REQUEST NAE event Brijesh Singh
2021-05-10 18:57 ` Peter Gonda
2021-05-10 20:14 ` Brijesh Singh
2021-05-10 21:17 ` Sean Christopherson
2021-05-11 18:34 ` Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 37/37] KVM: SVM: Advertise the SEV-SNP feature support Brijesh Singh
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